Coating composition



Patented Dec. 30, 1941 V COATING COMPOSITION Arnold J. Morway, Roselle,and Floyd L.

Roselle Park, N.

Miller,

J., assignors to Standard Oil Development Company,. a corporation oiDelaware No Drawing. Application October 19, 1938,

" Serial No. 235,777

7 Claims.

This invention relates to high molecular weight halogenated organiccompounds and compositions containing the same, and it relates moreparticularly to compositions containing in solution halogenated highmolecular weight hydrocarbon polymers, said compositions beingparticularly adapted to use as coating and impregnating agents and thelike.

This application is a continuation-impart of our co-pendlng applicationsSerial Nos. 749,072, filed October 19, 1934, and 170,120 filed October20, 1937.

The halogenated products of the present invention are produced by thehalogenation of substantially saturated, high molecular weight polymerswhich may be considered to have a chemical structure corresponding tothat of a very long chain of carbon atoms containing occasional sidechains of alkyl groups, such as methyl,

1' ethyl, etc. Such polymers, which may range from as low as 1,000 or5,000 up to 250,000 or more in molecular weight, although the preferredrange is between 5,000 and 200,000 molecular weight, are very stable andrelatively inert chemical compounds, being substantially completelysaturated with respect to hydrogen and having a very low iodine number,e. g. about "7 or less. Polymers of this type may be prepared bypolymerizing iso-olefins preferably having the gen-- eral formulaR(R')CICH2, where R and R represent aliphatlc hydrocarbon radicals,preferably alkyl radicals having 1 to 4 carbon atoms, such asisobutylene, Z-methyl-l-butene, and the like. The polymerization shouldbe carried out at low temperatures, for example, below '-10 C. or --50C. or even as low as 100 C. or lower, in the presence of a volatileinorganic halide catalyst, such as boron fluoride or complexes thereof,

for example BF3H2O, BF:H2SO4, etc. or other halides such as aluminumchloride, tin tetrachloride and the like. The polymerization ispreferably carried out in the presence 01' a suitable solvent for theisobutylene, such as liquefied normally gaseous hydrocarbons, e. g.propane, propylene, ethane, ethylene and the like, which may serve inthe double capacity of solvent as well as refrigerant by boiling andthereby removing the exothermic heat of polymerization.

The halogenated derivatives of the abovedescribed polymers are prepared,for example,

by contacting a halogen, such as chlorine, bromine or fluorine, with asolution of a high molecular weight hydrocarbon of the structuredescribed, either in the dark or in the presence of sunlight orartificial light, and in the presence or absence of a catalyst such asiodine; or, if the polymer is a liquid of low viscosity, thehalogenation maybe accomplished by simply passing the halogen throughthe polymer, without the use of a solvent. The solvent, if used, may beany one which is non-reactive with the halogen being used, or which, ifreactive therewith, will not cause any harmful effect on the highmolecular weight product. Carbon tetrachloride has been found verysuitable. Other solvents, such as carbon disulfide, may be used. Thetemperature to be used for the halogenation may vary depending upon anumber of factors, such as a desire to speed halogenation, theconcentration 0! materials and any catalytic promoting influences, butgenerally the temperature should be between the approximate limits of C.and C. The halogenatlon may be carried out at atmospheric pressure orconsiderably higher pressures, such as 5 to 50 or 100 atmospheres ormore, especially when carrying out the reaction at low temperature.

Various methods may be used for treating the high molecular weighthydrocarbon with the halogen. For example, chlorine may be bubbledthrough a carbon tetrachloride solution of the high molecular weightpolymer, or the chlorine maybe subjected to a countercurrent spray of asolution of the polymer. Another alternative is to carry out thehalogenation treatment in the presence of bases, e. g.,ca1cium ormagneslum oxides or carbonates, sodium carbonate or bicarbonate, etc.,or over water containing an insoluble carbonate, such as calciumcarbonate or magnesium carbonate, for the purpose of absorbing hydrogenhalide liberated by the reaction.

If desired, instead of first preparing the polymer in relatively pureform and then dissolving it in a suitable solvent and passing thehalogen through the solution, the original polymerization ofisobutylene, for example, may be carried out in the presence of carbontetrachloride or other solvent which will be suitable for thehalogenation, and then as soon as the polymerization process iscompleted the solution of the high molecular weight polymer may betreated immediately with a desired halogen, thereby avoiding the removalof the solvent used during the polymerization step and subsequentredissolving of the polymer in a solvent for the halogenation step.

After the halogenation has been completed to the desired degree, thehalogenated product may be separated from the solvent by precipitation,evaporation or other suitable means, such as pouring the solutionslowly, or else forcing it through a Jet under high pressure, intoboiling water, thereby'efiecting a steam distillation of Y the solvent.If desired, after the halogenation has been completed, the solution maybe blown with air or inert gas, such as nitrogen or hydrogen, at a'slightly elevated temperature, but preferably not above 100 C., in orderto remove hydrogen halide. Any traces still remaining may be r moved byfurther blowing the liquid with ammonia, or other volatile amine, aloneor mixed with air or inert gas, preferably at room ternperature orperhaps up to 40 or 50 C.

As an alternative, the product may be washed one or more times withdilute alkali, such as caustic soda ln order to remove any free hydrogenhalide remaining as a result of the halodroxide solutions; and (6) thetwo products are -about equal in ability to withstand artificial gentreatment. It may also, under some circumstances, be desirable to heatthe halogenated polymerv at a low temperature with a basic material,such as alcoholic potash, aqueous calcium hydroxide, sodium carbonatesolution, sodium bicarbonate, etc, to remove one or possibly morehalogen atoms and thereby produce a further,

stabilized product. A diilicultly volatile basic compound, preferably anaromatic amine such as monoethyl aniline or methyl naphthylamine, may beadded as a stabilizer (in proportions of 0.1 to 1% or so) to thefinished halogenated hydrocarbon.

The amount of halogen incorporated in the material depends upon theduration of the treatweatheringtests. The above comparisons withchlorinated rubber apply particularly to chlorinated isobutylene polymercontaining 40% or more of chlorine. An advantage in the use of thehalo-' chlorine content in two parts of toluene. Hence,

ment. 'As little as 1% to 10% and, as much as 70%, or more, may beincorporated, if desired.

The products prepared according to the present invention are'highmolecular weight halogenated hydrocarbons and they are either viscousliquids or brittle solids or substances of more or less intermediatecharacteristicsin the nature of plastic solids, depending upon thenature of the original material treated and the duration and type oftreatment. vFor example, solvent-free samples of a chlorinatedisobutylene polymer obtained by the chlorination of an approximately60,000 molecular weight isobutylene polymer and containing less thanabout 25% or chlorine'are' plastic at room temperature both with an without plasticizers or residual solvent, and will not break under a sharpblow; while solvent-free sampes of the same materialcontaining ofchlorine or higherarehard and quite brittle atv room temperature; andthe same material containing 60% chlorine is a white powder with noelastic properties. The chlorinated isobutylene polymer prepared asdescribed above and having a chlorine content in the range of 25-35% maybe either brittle or plastic depending upon the amount of plasticizer orresidual solvent present and upon the amount of molecular breakdownwhich has taken place during the halogenation process. Brittlenessincreases markedly with decreasing temperature.

The halogenated products, such as chlorinated isobutylene polymer, arecharacterized by their stability toward sunlight and artificial ultraviolet light, air, hot and cold water, and chemical agents, such assolutions of acids, bases and salts.

The products are also quite stable toward heat.

Chlorinated isobutylene polymer containing 40% chlorine and stabilizedby refluxing with a sodium hydroxide solution was found to be completelystable at a temperature of 100 C.

The products of this invention compare favoraby with chlorinated rubberas a base for chemically resistant coating compositions in that 1)rubber containing small amounts of chlorine is unstable while thepresent products are relatively stable; (2) the present products aremiscible with parafiin wax while chlorinated rub- 1 her is not; (3) thepresent products show greater stability toward ultra-violet light thanchlorinated rubber; (4) the two types of products are about equal inresistance to dilute hydrochloric acid; (5) the present products aresuperior to chlorinated rubber in resistance to sodium hy- 5 tion ofchlorinated isobutylene polymer finishes can be applied with less lossof solvent than those containing chlorinated rubber.

The high molecular weight halogenatedproducts of the present inventionare soluble in many volatile solvents which are suitable for thepreparation of coating compositions of various kinds.

As an example, chlorinated isobutylene polymer has been found to besoluble in the following welllmown solvents: ethyl acetate, amylacetate,v n-butyl laurate, isobornyl acetate, methyl cyclohexyl oxalate,butyl propionate, propyl propionate, ethyl propionate',n-butyicrotonate, sechexyl acetate, isopropyl acetate, mesityl oxide,di-isoprop yl ketone, diphenyl oxide, isopropyl esters of ,'fatty acidsproduced by the air oxidapetroleum waxes, methyl propyl ketone, methyl)ethyl ketone, methyl n-butyl ketone, methyl cyclohexanone, methyl n-amylketone, cyclohexanone, benzene, toluene, xylene, nitrobenzene, ethylbenzene, see-butyl benzene, ;c rotonaldehyde,pyridine, monochlorbenzene,carbon tetrachloride, chloroform, amyl naphthalene, dimethylnaphthalene, Dowtherm A," (diphenyl oxide and diphenyl), sec-hexylchloride, tetrachlorethane, dichloracetic .acld, DiethylCellosolve(diethyl ether of ethylene glycol), dichlorethyl ether, turpentine,tetralin and trimethyl aniline. This substance is also partially solublein acetone, diethyl ether and "Cellosolve Acetate" (acetic acid ester ofmonoethyl ether of ethylene glycol). The chlorinated isobutylenepolymers having a low chlorine content (about 25% or lower) and thosehaving a high chlorine content (substantially above 50%) are also quitesoluble in aliphatic petroleum hydrocarbon liquids, those havingintermediate chlorine contents being somewhat less soluble. The polymersof all degrees of chlorination are readily soluble in petroleumfractions containing aromatic material, such as sulphur dioxide extractsof petroleum distilates. Incorporation of the polymers in non-aromaticpetroleum fractions may be facilitated by the use of mutual solvents,such as aromatic hydrocarbons, chlorinated aliphatic hydrocarbons,ketones or esters.

The following examples illustrate various methods of preparing solutionsof chlorinated hydrocarbon polymers:

Ezrample 1 Chlorine gas is passed under pressure through vents in thebottom of a. tower packed with broken porcelain or spiral packing; whenthe tower has become saturated with the chlorine gas a solution ofisobutylene polymer in carbon tetrachloride is sprayed in at the top ofthe tower passing down through the chlorine gas and being removed atchlorinated proximate limits of 1 to removed by dissolving the thebottom of the tower and pumped back to the top of the same tower orother similar towers and the contact repeated until the chlorine contenthas reached the required amount.

The gaseous mixture removed at the top is finish is to be put. Forgeneral outside use the scrubbed free of HCl by passing through solidcaustic soda and again passed in at the bottom of the tower. The carbontetrachloride solution of isobutylene polymer is washed free of HCl by aslight carbonate washing and the carbon tetrachloride removed bydistillation.

Example 2 In the removal of traces of carbon tetrachloride from thewashed solution of chlorinated isobutylene polymer in carbontetrachloride, almost the total amount of solvent is removed by meredistillation, either atmospheric or under reduced pressure, theremaining traces of solvent being practically solvent-Tree chlorinatedproduct in close out naphtha with a boiling range close to the boilingpoint of carbon tetrachloride (76 C.) and redistilling. The solutionthus formed may be used in the preparation of coating compositionsaccording to the present invention.

Halogenated hydrocarbon polymers, prepared according to the invention,may be used in conjunction with suitable soft resins and pigments, withor without linseed oil, volatile solvents, etc., in the compounding ofpaints, lacquers, varnishes, enamels, etc., which are resistant tochemical and mechanical influences and also non-inflammable, or they maybe compounded with various resins alone, such as those prepared frompetroleum hydrocarbons by various known methods, in order to improve theproperties of such resins.

In coating compositions prepared according to the present invention, theamount of halogenated hydrocarbon polymer may be between the ap- 70% byweight of the between the limits 01 upon the other constitvehicle, andpreferably about 5 to 30% depending uents present.

Chlorinated hydrocarbon polymer finishes may, for example, be preparedin the same manner as ordinary lacquers. The finish dries by theevaporation of the solvent to a lustrous, adhesive film of greatprotective power and pleasing appearance. Such finishes are ofparticular value where unusually great resistance to chemical action isdesired. Panels-of chlorinated isobutylene polymer enamels have, forexample, been found to be in good condition after immersion for weeks in40% sulfuric acid, 40% lactic acid and 40% sodium hydroxide, and afterimmersion for 5 weeks in 10% hydrochloric acid. Also, the exposure ofsimilar enamels to sulfuric acid and sulfur dioxide and trioxide fumesin refinery acid treating tanks showed them to be more resistant thanthe highest grades of oil base paint. Enamels of this kind have alsobeen found to be especially resistant under severe weatheringconditions.

For finishes which are not subject to severe abrasions a chlorinatedisobutylene polymer of low chlorine content and high elasticity hasibeenfound to be particularly desirable, since this materlal requires lessplasticizer and hence gives a film of increased life and greaterchemical resistance. Such films are preferably pigmented to obtainproper drying. With the hardervarieties of chlorinated products, such aschlorinated isobutylene polymer containing above 45% chlorine, it may benecessary to use as much as 30% of a plasticizer, depending upon the useto which the addition of drying oils and of drying oil-modified alkydresin mixtures is preferred. Tricresyl phosphate and dibutyl phthalateare especially suitable plasticizers, although many other commerciallyavailable plasticizers, such.as dibutyl tartrate, raw, blown, or boiledlinseed oil, boiled tung oil, methyl cyclohexyl adipate, etc. are alsocompatible with chlorinated isobutylene polymer. Film plasticity ispreferably obtained by changing the type oi. chlorinated polymer usedrather than by adding more plasticizer. For finishes to be applied toconcrete, stucco, plaster, cement, asbestos boards, brick and similarsurfaces it is preferable to use a plasticizer which will not saponify,such as chlorinated diphenyl, highly aromatic oils and terpenebalsams.

In general, the preparation of a coating composition according to thepresent invention, where a pigment is not used, is accomplished by firstmeasuring out the solvent mixture, then adding the halogenated polymerwith vigorous agitation to the solvent mixture and finally adding theplasticizer and any additional resins to the solu tion. In order thatthe film may dry properly, it is desirable that the solvents bebalanced, i. e., that sufilcient high boiling solvent be used in themixture to allow the film to remain open until substantially all thesolvent is evaporated. In the preparation of coating compositionscontaining pigments, it is desirable to measure out the solvent mixture,add a portion of the solvent to the halogenated polymer with vigorousagitation to make a viscous solution, grind the pigment and theplasticizer, if any is to be used, in the polymer solution, and add thebalance of the solvent Parts Chlorinated isobutylene polymer Cl) 200Bodied tung oil Hydrogenated methyl abietate 60 Iron oxide 150 Thepigment is ground in a paste formed from the other constituents.Sufllcient thinner is added to bring the mixture to the correct brushingviscosity. A suit-able thinner consists of parts of a sulfur dioxideextract (boiling range about 275350 F., kauri butanol value 78.7) of apetroleum distillate, parts of a sulfur dioxide extract (boiling rangeabout 350-410 F., kauri butanol value 73.7) of a petroleum distillate,and 100 parts of a straight run petroleum naphtha (boiling range about167-237 R).

In the preparation of lacquers according to the present invention, thehalogenated polymer is dissolved in the volatile solvent, and otheringredients, such as plasticizers, preservatives, etc., are added asdesired. A typical lacquer formula is the following:

Parts by weight Chlorinated isobutylene polymer solution 15 'Wet 1/2sec; nitrocellulose l0 Dibutyl phthalate 5 Red pigment 20 a mixture-consisting of 50 parts of toluol, 25,

parts of ethyl acetate, 5 parts of butanol and 50 parts of butylacetate.

Varnishes may be similarly prepared from the halogenated polymers, and atypical formula is the following:

Parts Chlorinated isobutylene polymer solution;- Hydrogenated methylabietate The polymer solution consists of 60 parts of chlorinatedisobutylene polymer (45% C1) and 40 parts of a sulfur dioxide extract(boiling range about 200-275 C., kauri butanol value 72.5) of apetroleum distillate. The above mixture is thinned with a mixtureconsistingof 40 parts of ethyl acetate and 60 parts of the sulfurdioxide extract.

Enamels may be similarly prepared, adding pigments as desired.

In all of the above examples of formulas for paints, lacquers andvarnishes, the chlorinated polymer used contained about 45% of chlorineand was prepared by passing chlorine through a solution of isobutylenepolymer of molecular weight of about 60,000 to 70,000 incarbontetrachloride in the presence of sunlight.

A water emulsion of a halogenated polymer, such as chlorinatedisobutylene polymer, may be used to treat cloth ,or paper to render thelatter resistant to flames and chemicals. Such an emulsion may beprepared by adding an emulsitying agent, such as oleic acid, to theresin dissolved in an aromatic solvent, and mixing this solution with asolution of triethanol amine in water.

A waterproof and chemical-proof fabric suitable for raincoats, showercurtains, etc., may be made by calendering cloth with chlorinatedisobutylene polymer alone or mixed with montan, carnauba and spermacetiwaxes and with chlorinated naphthalene.

Halogenated hydrocarbon polymer coatings may be applied in any wellknown manner," such as spraying, brushing, flowing, dipping or. rollercoating. Such coatings are most useful on metal surfaces which should befree of mill scale, rust, grease or dirt. Sand blasting or roughening ofthe surface to be coated with awire brush will facilitateadhesion. Sincethe finishes remain soluble after drying, they are preferably applied inonly, one coat, when applied by brushing, in order to avoid brushingover previously coated areas. Lacquers containing halogenatedhydrocarbon polymers can be easily sprayed without webbing and othermechanical difficulties ordinarily encountered in the spray applicationof lacquers of this type. A plurality of thin coats requires less timeand gives better films than a few thick coats. A short bake at a lowtemperature (below about 90 C.) is recommended for small articles,especially those coated withclear finishes. g

The saturated high molecular weight polymers may also be mixed with wax,resinsymineral and vegetable oils, chloraromatics, esters, and the Theisobutylene polymer was prepared by contacting isobutylene with a boronfluoride catalyst at about like, prior to or after halogenation. Whenblended in mineral oils, the chlorinated polymer may be used inconjunction with oxidation inhibiting amines.

The halogenated hydrocarbon polymers of the present invention are usefulas fire-resistant impregnating agents, for impregnating various types ofporous or fibrous materials, such as wood, oil, paper, etc., especiallywhen incorporated in small quantities with a wax, such as a paramnicwax.

v'lI'he polymers may frequently serve to advantage as solvents orplasticizers. For delu'stering artificial silk, these compounds may bemixed with an inert organic' material of an oily or waxy nature, such aspetroleum oil, petroleum jelly and paraihn wax, and the mixture added tosolutions of artificial silk to be spun.

Itis not intended that the invention be limited to the particularexamples, modifications and embodiments which have been given merely forthe sake of illustration, but only by the appended claims in which it isintended to claim all novelty inherent in the invention as broadly asthe prior art permits. Y

What we claim is:

1. A paint composition comprising a chlorinated isobutylene polymer, adrying oil and a pigment.

2. A paint composition comprising 200 parts by weight of a chlorinatedisobutylene polymer containing approximately of chlorine, prepared bythe chlorination of an isobutylene polymer of molecular weight ,of about60,000 to 70,000, parts by weight of bodied tung oil, 60 parts by weightof hydrogenated methyl abietate and parts by weight of iron oxide.

3. A coating composition comprising a substantially saturated linearhydrocarbon polymer of the aliphatic series having a molecular weight inexcess of about 1,000, having a plurality of short allwl side chains andhaving chemically combined therewith at least 1% of a halogen, saidpolymer being dissolved in a drying oil.

4.'A coating composition comprising a polymer of an isoolefln having theformula a where R and R. represent alkyl radicals havingone to fourcarbon atoms, said polymer having chemically combined therewith at least1% by weight of a halogen and being dissolved in a drying oil. I

5. A coating composition comprising a chicrinated isobutylene polymerdissolved in a drying oil.

6. A coating composition comprising a substantially saturated linearhydrocarbon polymer of the aliphatic series having a molecular weight inexcess of about 1,000, having a plurality of short alkyl side chains andhaving chemically combined therewith at least 1% of chlorine, saidpolymer being dissolved in a drying oil.

7. A coating composition comprising a chlorinated isobutylene polymercontaining at least 10%, by weight, of chlorine and obtained by thechlorination of an isobutylene polymer of a molecular weight from 5,000to 200,000, said chlorinated polymer being dissolved in a drying oil.

ARNOLD J. MORWAY. FLOYD L. MILLER.

